In vitro and in vivo availability of commercial prednisone tablets.

A three-way crossover bioavailability study was performed using nine adult male volunteers with three different commercial prednisone tablets. Plasma samples were assayed for prednisolone, the active metabolite of prednisone, by a radioimmunoassay method. Statistical analysis showed significant differences in the rate of appearance of prednisolone in plasma but not in the amount converted to prednisolone. The results suggest that differences in in vivo rates of appearance of prednisolone in plasma correlate with in vitro rates of dissolution.